Thermal and pulsed electric fields pasteurization of apple juice: Effects on physicochemical properties and flavour compounds

Abstract

Apple juice, extracted from golden delicious fruits, was pasteurized using a pulsed electric field (PEF) treatment and compared with a conventional high temperature-short time (HTST) method. The PEF treatment was carried out using a PEF laboratory unit, set with a bipolar pulse (4 mu s wide), an intensity of 35 kV/cm, and a frequency of 1200 pulses per second (pps). The thermal pasteurization was performed at 90 degrees C for 30 s with an adapted laboratory set-up. Effects of variables of both treatments on pH, total acidity, phenolics content, and volatile compounds were investigated. While minimal variability was observed in pH and no significant changes were detected in acidity, phenolics content and volatile compounds concentration showed statistical significant differences between treatments. In general, these measured variables were less affected by the PEF treatment than by the thermal pasteurization